1. Field of the Invention
The present invention relates to an electric technique field, and more particularly to an adjusting device of an output voltage of a switch power supply, an adjusting method thereof and an integrated chip.
2. Description of the Prior Art
With the increasing use of computer equipment, a computer system requires a switch power supply to be capable of providing a stable and precise supply voltage. The supply voltage is not allowed to beyond a required voltage range, otherwise the computer system will automatically shut down, and even easily burn out. Therefore, most of the switching power supplies dispose an output voltage-adjusting module. When the output voltage varies, it may be automatically adjusted by the electrical circuit characteristic.
In the manufacturing process of the switch power supply, an output voltage point is set by adjusting the value of a variable resistor, and is fixed by glue dispensing method after setting. The traditional method of setting and testing the output voltage point is as follows: the first step is setting a current range and a voltage range of a DC electronic load, the second step is connecting the switch power supply to the DC electronic load, the third step is tuning the variable resistor until the output voltage of the product reaches the preset voltage range of the DC electronic load, and to finish the adjustment when the DC electronic load displays “PASS”, and the fourth step is dispensing glue on one point of the variable resistor to prevent the variation of the variable resistor.
However, every operation step above is performed by manual operation, seriously blocking the improvement of productivity. Moreover, the glue dispensed on the variable resistor can easily expand with heat and contract with cold when drying, so the fixed variable resistor may be varied and the set output voltage point may be displaced. This will seriously influence the product quality.